A wide variety of techniques are known for forming and otherwise working metallic tubular elements. Such techniques include turning, drawing, extrusion, boring, and the like. In all of these techniques, mechanical force is applied to the workpiece with the forming or cutting tools, thereby effecting the desired shaping or other work operations.
Despite the wide variety of well-known metal working techniques, the desired shaping and formation of some types of tubular elements remains labor-intensive and time-consuming. By way of example, the formation of tubular bodies to provide the components of various types of musical instruments has heretofore been quite labor-intensive. A typical metallic tubular body such as for a flute, piccolo, saxophone, or the like, is ordinarily generally elongated, and can include both cylindrical and/or tapering sections. Additionally, many such components include a plurality of "tone" holes with which movable keys are associated for achieving the desired tonal effect.
In the past, it has been necessary to first shape such a tubular body to define the desired cylindrical and/or tapered configuration, with any steps or like changes in cross-section as required. Tone holes must then be formed in the tubular body, with small cylindrical "risers" or "chimneys" then individually soldered into position at each tone hole to provide a flat, circular surface for receiving the respective key.
In an effort to facilitate efficient and economical manufacture of musical instruments, the present tube-forming technique was developed. While the method and apparatus of the present invention are particularly suited for forming the tubular bodies used in musical instruments, it will be recognized that the economy and versatility provided by the metal-forming techniques of the present invention permit the invention to be used for a wide variety of applications.